change auth for cats api (public-apis#795)

Author: juristr

README.md

@@ -61,7 +61,7 @@ Please note a passing build status indicates all listed APIs are available since
 API | Description | Auth | HTTPS | CORS |
 |---|---|---|---|---|
 | [Cat Facts](https://alexwohlbruck.github.io/cat-facts/) | Daily cat facts | No | Yes | Unknown |
-| [Cats](https://thecatapi.com/docs.html) | Pictures of cats from Tumblr | No | Yes | Unknown |
+| [Cats](https://thecatapi.com/docs.html) | Pictures of cats from Tumblr | `apiKey` | Yes | Unknown |
 | [Dogs](https://dog.ceo/dog-api/) | Based on the Stanford Dogs Dataset | No | Yes | Yes |
 | [HTTPCat](https://http.cat/) | Cat for every HTTP Status | No | Yes | Unknown |
 | [IUCN](http://apiv3.iucnredlist.org/api/v3/docs) | IUCN Red List of Threatened Species | `apiKey` | No | Unknown |